<?php // $Id: lib.php,v 1.45.2.6 2008/03/02 15:15:07 moodler Exp $

///////////////////////////////////////////////////////////////////////////
//																	   //
// NOTICE OF COPYRIGHT												   //
//																	   //
// Moodle - Modular Object-Oriented Dynamic Learning Environment		 //
//		  http://moodle.com											//
//																	   //
// Copyright (C) 1999 onwards  Martin Dougiamas  http://moodle.com	   //
//																	   //
// This program is free software; you can redistribute it and/or modify  //
// it under the terms of the GNU General Public License as published by  //
// the Free Software Foundation; either version 2 of the License, or	 //
// (at your option) any later version.								   //
//																	   //
// This program is distributed in the hope that it will be useful,	   //
// but WITHOUT ANY WARRANTY; without even the implied warranty of		//
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the		 //
// GNU General Public License for more details:						  //
//																	   //
//		  http://www.gnu.org/copyleft/gpl.html						 //
//																	   //
///////////////////////////////////////////////////////////////////////////

require_once($CFG->dirroot.'/lib/gradelib.php');
require_once($CFG->dirroot.'/grade/lib.php');
require_once($CFG->dirroot.'/grade/export/grade_export_form.php');

/**
 * Base export class
 */
class grade_export {

	var $plugin; // plgin name - must be filled in subclasses!

	var $grade_items; // list of all course grade items
	var $groupid;	 // groupid, 0 means all groups
	var $course;	  // course object
	var $columns;	 // array of grade_items selected for export

	var $previewrows;	 // number of rows in preview
	var $export_letters;  // export letters
	var $export_feedback; // export feedback
	var $userkey;		 // export using private user key

	var $updatedgradesonly; // only export updated grades
	var $displaytype; // display type (e.g. real, percentages, letter) for exports
	var $decimalpoints; // number of decimal points for exports
	/**
	 * Constructor should set up all the private variables ready to be pulled
	 * @param object $course
	 * @param int $groupid id of selected group, 0 means all
	 * @param string $itemlist comma separated list of item ids, empty means all
	 * @param boolean $export_feedback
	 * @param boolean $export_letters
	 * @note Exporting as letters will lead to data loss if that exported set it re-imported.
	 */
	function grade_export($course, $groupid=0, $itemlist='', $export_feedback=false, $updatedgradesonly = false, $displaytype = GRADE_DISPLAY_TYPE_REAL, $decimalpoints = 2) {
		$this->course = $course;
		$this->groupid = $groupid;
		$this->grade_items = grade_item::fetch_all(array('courseid'=>$this->course->id));

		$this->columns = array();
		if (!empty($itemlist)) {
			$itemids = explode(',', $itemlist);
			// remove items that are not requested
			foreach ($itemids as $itemid) {
				if (array_key_exists($itemid, $this->grade_items)) {
					$this->columns[$itemid] =& $this->grade_items[$itemid];
				}
			}
		} else {
			foreach ($this->grade_items as $itemid=>$unused) {
				$this->columns[$itemid] =& $this->grade_items[$itemid];
			}
		}

		$this->export_feedback = $export_feedback;
		$this->userkey		 = '';
		$this->previewrows	 = false;
		$this->updatedgradesonly = $updatedgradesonly;
		
		$this->displaytype = $displaytype;
		$this->decimalpoints = $decimalpoints;
	}

	/**
	 * Init object based using data from form
	 * @param object $formdata
	 */
	function process_form($formdata) {
		global $USER;

		$this->columns = array();
		if (!empty($formdata->itemids)) {
			foreach ($formdata->itemids as $itemid=>$selected) {
				if ($selected and array_key_exists($itemid, $this->grade_items)) {
					$this->columns[$itemid] =& $this->grade_items[$itemid];
				}
			}
		} else {
			foreach ($this->grade_items as $itemid=>$unused) {
				$this->columns[$itemid] =& $this->grade_items[$itemid];
			}
		}

		if (isset($formdata->key)) {
			if ($formdata->key == 1 && isset($formdata->iprestriction) && isset($formdata->validuntil)) {
				// Create a new key
				$formdata->key = create_user_key('grade/export', $USER->id, $this->course->id, $formdata->iprestriction, $formdata->validuntil);
			}
			$this->userkey = $formdata->key;
		}

		if (isset($formdata->export_letters)) {
			$this->export_letters = $formdata->export_letters;
		}

		if (isset($formdata->export_feedback)) {
			$this->export_feedback = $formdata->export_feedback;
		}

		if (isset($formdata->previewrows)) {
			$this->previewrows = $formdata->previewrows;
		}

	}

	/**
	 * Update exported field in grade_grades table
	 * @return boolean
	 */
	function track_exports() {
		global $CFG;

		/// Whether this plugin is entitled to update export time
		if ($expplugins = explode(",", $CFG->gradeexport)) {
			if (in_array($this->plugin, $expplugins)) {
				return true;
			} else {
				return false;
		  }
		} else {
			return false;
		}
	}

	/**
	 * Returns string representation of final grade
	 * @param $object $grade instance of grade_grade class
	 * @return string
	 */
	function format_grade($grade) {
		return grade_format_gradevalue($grade->finalgrade, $this->grade_items[$grade->itemid], false, $this->displaytype, $this->decimalpoints);
	}

	/**
	 * Returns the name of column in export
	 * @param object $grade_item
	 * @param boolena $feedback feedback colum
	 * &return string
	 */
	function format_column_name($grade_item, $feedback=false) {
		if ($grade_item->itemtype == 'mod') {
			$name = get_string('modulename', $grade_item->itemmodule).': '.$grade_item->get_name();
		} else {
			$name = $grade_item->get_name();
		}

		if ($feedback) {
			$name .= ' ('.get_string('feedback').')';
		}

		return strip_tags($name);
	}

	/**
	 * Returns formatted grade feedback
	 * @param object $feedback object with properties feedback and feedbackformat
	 * @return string
	 */
	function format_feedback($feedback) {
		return strip_tags(format_text($feedback->feedback, $feedback->feedbackformat));
	}

	/**
	 * Implemented by child class
	 */
	function print_grades() { }

	/**
	 * Prints preview of exported grades on screen as a feedback mechanism
	 */
	function display_preview() {

		print_heading(get_string('previewrows', 'grades'));

		echo '<table>';
		echo '<tr>';
		echo '<th>'.get_string("firstname")."</th>".
			 '<th>'.get_string("lastname")."</th>".
			 '<th>'.get_string("idnumber")."</th>".
			 '<th>'.get_string("institution")."</th>".
			 '<th>'.get_string("department")."</th>".
			 '<th>'.get_string("email")."</th>";
		foreach ($this->columns as $grade_item) {
			echo '<th>'.$this->format_column_name($grade_item).'</th>';

			/// add a column_feedback column
			if ($this->export_feedback) {
				echo '<th>'.$this->format_column_name($grade_item, true).'</th>';
			}
		}
		echo '</tr>';
		/// Print all the lines of data.

		$i = 0;
		$gui = new graded_users_iterator($this->course, $this->columns, $this->groupid);
		$gui->init();
		while ($userdata = $gui->next_user()) {
			// number of preview rows
			if ($this->previewrows and $this->previewrows <= $i) {
				break;
			}
			$user = $userdata->user;
			// if (empty($user->idnumber)) {   // Not sure why this was here, ccommented out for MDL-13722
			//	 continue;
			// }
			
			$gradeupdated = false; // if no grade is update at all for this user, do not display this row
			$rowstr = '';
			foreach ($this->columns as $itemid=>$unused) {
				$gradetxt = $this->format_grade($userdata->grades[$itemid]);
				
				// get the status of this grade, and put it through track to get the status
				$g = new grade_export_update_buffer();
				$grade_grade = new grade_grade(array('itemid'=>$itemid, 'userid'=>$user->id));
				$status = $g->track($grade_grade);

				if ($this->updatedgradesonly && ($status == 'nochange' || $status == 'unknown')) {
					$rowstr .= '<td>'.get_string('unchangedgrade', 'grades').'</td>';
				} else {
					$rowstr .= "<td>$gradetxt</td>";
					$gradeupdated = true;
				}
				
				if ($this->export_feedback) {
					$rowstr .=  '<td>'.$this->format_feedback($userdata->feedbacks[$itemid]).'</td>';
				}
			}

			// if we are requesting updated grades only, we are not interested in this user at all			
			if (!$gradeupdated && $this->updatedgradesonly) {
				continue; 
			}

			echo '<tr>';
			echo "<td>$user->firstname</td><td>$user->lastname</td><td>$user->idnumber</td><td>$user->institution</td><td>$user->department</td><td>$user->email</td>";		   
			echo $rowstr;
			echo "</tr>";
			
			$i++; // increment the counter
		}
		echo '</table>';
		$gui->close();
	}

	/**
	 * Returns array of parameters used by dump.php and export.php.
	 * @return array
	 */
	function get_export_params() {
		$itemids = array_keys($this->columns);

		$params = array('id'				=>$this->course->id,
						'groupid'		   =>$this->groupid,
						'itemids'		   =>implode(',', $itemids),
						'export_letters'	=>$this->export_letters,
						'export_feedback'   =>$this->export_feedback,
						'updatedgradesonly' =>$this->updatedgradesonly,
						'displaytype'	   =>$this->displaytype,
						'decimalpoints'	 =>$this->decimalpoints);

		return $params;
	}

	/**
	 * Either prints a "Export" box, which will redirect the user to the download page,
	 * or prints the URL for the published data.
	 * @return void
	 */
	function print_continue() {
		global $CFG;

		$params = $this->get_export_params();


		print_heading(get_string('export', 'grades'));

		echo '<div class="gradeexportlink">';
		if (!$this->userkey) {	  // this button should trigger a download prompt
			print_single_button($CFG->wwwroot.'/grade/export/'.$this->plugin.'/export.php',
								$params, get_string('download', 'admin'));

		} else {
			$paramstr = '';
			$sep = '?';
			foreach($params as $name=>$value) {
				$paramstr .= $sep.$name.'='.$value;
				$sep = '&amp;';
			}

			$link = $CFG->wwwroot.'/grade/export/'.$this->plugin.'/dump.php'.$paramstr.'&amp;key='.$this->userkey;

			echo get_string('download', 'admin').': <a href="'.$link.'">'.$link.'</a>';
		}
		echo '</div>';
	}
}

/**
 * This class is used to update the exported field in grade_grades.
 * It does internal buffering to speedup the db operations.
 */
class grade_export_update_buffer {
	var $update_list;
	var $export_time;

	/**
	 * Constructor - creates the buffer and initialises the time stamp
	 */
	function grade_export_update_buffer() {
		$this->update_list = array();
		$this->export_time = time();
	}

	function flush($buffersize) {
		global $CFG;

		if (count($this->update_list) > $buffersize) {
			$list = implode(',', $this->update_list);
			$sql = "UPDATE {$CFG->prefix}grade_grades SET exported = {$this->export_time} WHERE id IN ($list)";
			execute_sql($sql, false);
			$this->update_list = array();
		}
	}

	/**
	 * Track grade export status
	 * @param object $grade_grade
	 * @return string $status (unknow, new, regrade, nochange)
	 */
	function track($grade_grade) {

		if (empty($grade_grade->exported) or empty($grade_grade->timemodified)) {
			if (is_null($grade_grade->finalgrade)) {
				// grade does not exist yet
				$status = 'unknown';
			} else {
				$status = 'new';
				$this->update_list[] = $grade_grade->id;
			}

		} else if ($grade_grade->exported < $grade_grade->timemodified) {
			$status = 'regrade';
			$this->update_list[] = $grade_grade->id;

		} else if ($grade_grade->exported >= $grade_grade->timemodified) {
			$status = 'nochange';

		} else {
			// something is wrong?
			$status = 'unknown';
		}

		$this->flush(100);

		return $status;
	}

	/**
	 * Flush and close the buffer.
	 */
	function close() {
		$this->flush(0);
	}
}
?>
